Electric reversing device for tapping machines



July 17, 1928.

B. S. T. BISHOP ET AL ELECTRIC REVERSING DEVICE FOR'TA BPING MACHINES Filed Feb. 5, 1926 2 Sheets-Sheet 2 27 .fiffficlskap Emery-A. ficobson 3y own/aye! July 17, 1928.

B. S. T. BISHOP ET AL ELECTRIC REVERSING DEVICE FOR TAPPING MACHINES 2 Sheets-Sheet 3 Filed Feb. 5, 1926 r 0 W J 62 J 2 9 a 4. o a

o n J 6 a a 1 d 6 0 m a a. k1 a 3 M, 4 a 9 7 a 1 z a ,5 W o Q J I} 6 6 a 4 3 3 0 a 4 0 3 Patented July 17, 1928.

@oNiT-E srnrss BENJ'AMIN"SL:T. BISHOP, OF SHREWSBURXZ'AND HENRY A. JACOBSON, F WORCESTER,

.MASSACHU SETTS, ASSIGINORS TO .LELAND-GIFFORD COMPANY, 11' CORPORATION OF MASS CH SETTS.

ELECTRIC *REVERSING DEVICE FOR- TAPPING MACHINES.

Application filed February 3, 1926. Serial No. 85,693.

This invention-is articularl I desi ned for use on combined drilling and tappingmachines driven by an electric motor and relates to' the reversing ofthe spindle so that .it-will turninto the work,.reverseauto- ,mat-ically, turn out again and then repeat the. operation without .attention offiche operator.

. The. principal obj ectsv of the invention in addition to this areto. provide a handle or lever. for. reversing purposes with means con- I .nected the rewithhadapted to be operated .automatically sothat the machine can be reversed in the regular way automatically or by, hand; at. the willof the operator towprovide improved means for mounting the operating member'for controlling the automatic. reverse and to provide improvements in. :the switch. i j

Reference ,is. to be :had. .to the accompanyingdrawingsin which Q.Fig.. 1: is.a.:side.view of a part of [a drilling machine with a preferred embodiment of this invention applied thereto j Fig.5 21.,is. a; plan of the. attachmentwith the motor. shown in .dotted lines "Fig. 3 is a sectional view on the line 3-3 f'Fi -l; I

, Fig.,.4','s ,aL central. sectional view of the tion; I

.,Figs.., .5. and 6 Far-e sectional views on. the lines 5-:5 and. 6.6. respectively of Figs; and

.Eign'Eis a diagramm'atic viewof the electrical connections.

.We haveshown the invention asapplied to adrill used. for tapping. and comprising a frame 10 with amoto'r 11 at the'top mountednon avertical axis. ,The machine comprisesaspindle.12 which rotates in the quill 13. .1The .qui ll ,moves up and down with. the. spindle either the a ,usualhand or-power feed anduthe tool is screwedinto thework. in case of tapping. On the quill 'at.lthe.,rear there. is :a. projection constitutswitch =.proper with. parts. shown in: elevainganiarm having a pivot stud 14 on which is mounteda. link 15 with a-spring pin 16 forengaging inia-notch 17in the arm on the. quill. This. .leveris, provided in a circularhhub that surrounds the stud. so that the connection canieasil be detached in case the machine isopera-te --by hand, when not tapping. Qn ,the .quillarmpare a; pair of the spindle.

U-shaped yoke 20 having a notch 211at one side for receiving a rod 22. -T his notch is open at the end to receive this rod. It will lice-understood that the arm 15 moves up and i'down withthequill but doesnot rotate with The rod 22 is provided withtwo adjustable stops or dogs 23 and with the rise or fall of the spindle. these dogs at either end will move to raise or lower this rod. The rod. 22- is connected to an operating lever 24; having a handle 25 for reversing, the switch manually at" any time during the'operation. The lever24l is connected with a rod26 which in turn is connected to an arm 27 fixed on an operating plate 28- and oscillatable about the axis of aqshaft 29. This shaft is mounted .in a switchboxv 30 and extends through it centrally. It willv be obvious that the operating plate 28 isoscillated back and forthat the ends of the stroke, of the spindle. It has aprojection 31 for aQpurpose to be described.

On the. shaft 29 is keyedtheplate. 32- which is provided -.with. a pair of notches 34 Ron opposite sides .of the center which have walls or abutments at their ends constituting stops. Alsothis plate is provided with two opposite projections or teeth'36 which are engaged by a pair of latches 37 pivoted on the casing 30 atopposite points but both extending in the same general direction from the pivots. Spring H pressed plungers 38 bear on-the .latches andforce them yieldingly inward. Each latch also has a pin 39 projecting at right angles from the surface.

,These latches are intended. to engage the teeth 36.

Loosely mounted on the shaft 29 aretwo plates 40 and 47. T heplate 10 is provided witha convex projection ifiwhich is located to engage one of theflpins 39 as this plate turns to release that latch. .11; is, also provided witha pin 42 located in one ofthe notches 34 for the purpose of turning. the p1ate'32 as will be seen. The plate also has another pin 43 to which is attached a spring tewhich is connected with a pin 45 on. the plate't'Z. This plate 47 has a convex projection 41 similar to the projection 516 on the plate-10 and has the samefunction relative vis produced.

to the other latch. This plate also has pin 48 like the pin 42 and acting in the opposite notch 34.

It will be seen also that both plates have end projections extending substantially to 42. Whenthe projection 31 starts back upwardly, it swings the plate 47 stretching the spring 44 until its projection 41 engages the proper pin 39 and releases the latch. Now the plate 40 is released and the spring 44 swings plates 40 and 32 in the same direction until latch 37 engagesnotch36. If spring 44 fails to move the plate 32 far enough to engage latch 37 in notch 36, then the projection 31 moves the plate 47 further until the pin 48 engages theend of the notch 34, latching 37 in notch 36.

When the arm 27 is swung back again it will have to move a little ways before engaging the free plate 40 and then it will swing that and its convex projection 46 will engage the lower pin 39 releasing this latch from the tooth 36 by which the plate 32 was locked in its extreme position. The continued movement of the arm 27 swings the plate32 back until locked by the latch 37 at the top. Thus one complete oscillation The shaft 29 is of course oscillated in bearings on the casing 30 as has been seen. The central portion of this shaft is square and provided with an insulating block 50 which necessarily oscillates with it. This is formed of insulating material-and has a metal support 61 carrying two contacts 51 ateach end. Similar contacts 52 are carried by an opposite support 60. The contacts 52 are connected across by two wires 53 which cross each other as shown in Fig. 4. These contacts are of usual form having springs for yieldingly holding them in position. An insulating piece 55 projects from the block 50 and keeps away the wires 53 where they cross and also electrically divides the metallic support 60. The two contacts 51 at one side of the block 50 are connected to the other contacts 52 by the support 61 carried by the block.

Terminals 56 are shown as located opposite eachother and mounted on yielding supports carried by posts 58 and connected with the line inthe usual manner.

The shaft oscillates from one extreme position to the other and two contacts 52 alternately come into contact with the terminals 56. In that way contact is established as shown in Fig. 5, from the terminal on one side, through the wire 53 to the conductor 54 on the other side and to the other contacts 51 so the currentis completed in one direction. Now when the parts oscillate to the opposite position, contact 52 at the bottom engages the terminal 56. The current goes through 'th'econduc'tor 54, and is conducted at thelcft side directly to the other one of the contacts 51. It will be seen that in one case the current crosses over and in the other case it is directed straight through so that in one case it is delivered to the machine in-one directionand in the other case in the other direction.

This constitutes a simple way of reversing the current in the. machine and provides a device which can be operated by hand as well have illustrated and de-.

comprising an oscillatable plate connected to be operated by said rod, a shaft on which the plate is movable, meansfor'alternately connecting said plate with the shaft and disconnecting it therefrom, and means for. conducting a current through the switch alternately in opposite directions as the plate is oscillated.

2. The combination in a reversin'gswitch, of a casing, a shaft therein, a. plate oscillable on said shaft and having a projection extending from it, means for oscillating. said plate, twoplates mounted to swing freely on the shaft and projecting to a point to be engaged by said projection as said .first named plate oscillates, whereby said plates will be moved by the projection, means. operated by saidplates for positively turning the shaft in one direction by one plate and in the opposite direction by theother plate, and means in the casing. for connecting a source of power in opposite directions according to the position of the plate.

3. In a reversing switch. the combination with a .casingand a shafttherein having means for reversing an electric current, of a plate oscillable on said shaftby external means and having a projectionextending from it, two plates mounted toswing freely on the shaft and projecting to a point to be engaged by said projection as said. first named plate oscillates, and means operated by said plates for positively turning the shaft in one direction by one plate and in the opposite direction by the other plate.

"4. In a; reversing switch, the combination with a; casing andnashaft therein having means for reversing an electric current, of a plate oscillable on, said shaft by external means 1 and having a 1 projection extending from it, two plates mounted to swingfreely on the shaft and projecting to a point'to be engagedby said projection as said first named plate oscillates, whereby said-plates will be moved by the projection, yielding means for swinging the plates toward each other to reduce the space between them in which the projection is located, and means operatedby said plates for positively turning the shaft in one direction by one plate the fixed plate alternately back and forth as the first named plate is oscillated.

6. In a reversing switch for the purpose described, the combination of a casing, an oscillatable shaft mounted in said casing, a plate fixed on the shaft and having a pair of elongated notches oppositely located, two

plates freely oscillatable on said shaft each All having a pin projecting into one of said notches, a spring connecting said free plates, and an oscillatable operating plate at the end of the casing having a projection for engaging the two free plates and operating them suiiiciently to stretch the spring and swing the shaft back and forth as the operating plate is oscillated.

7. In a reversing switch for the purpose described, the combination of a casing, an

oscillatable shaft mounted in said casing, a plate fixed on the shaft, two plates freely oscillatable on said shaft each having a projection for engaging the fixed plate to lock the free plate to it, an oscillatable operating plate at the end of the casing having a projection for engaging the two free plates and operating them alternately to swing the shaft back and forth as the operating plate oscillates, spring latches for engaging the fixed plate in certain positions and looking it against motion, said free plates having convex projections thereon adapted to engage said latches and disengage them from the fixed plate for unlocking the same alternately as the operating plate oscillates.

8. In a reversing switch for the purpose described, the combination of a casing, an oscillatable shaft mounted in said casing, a plate fixed on the shaft and having a pair of elongated notches oppositely located, two plates freely oscillatable on said shaft each having a pinwp'rojecting-into 'one; of-fisa-id notches tolock the freed plates 1505 13116 Y fixed plate, a spring connecting' saidfreeplates,

an oscillatable operating 1:)late'at-:the end-of the casinghaving a. projection-for engaging the two free plates alternately and operating them sufficiently to stretch the-spring, and a pair of spring latches fonengaging the fixed plate in certainpositionsandlocking it alternately against motion in opposite directions, wherebywhen either l-atch is*released the fixed plate and one of the=free .plates are released to permitthe springto turn them ,and -the shaft, saidfifreegplates having convex projections thereon adapted to engage said latches and disengage them from the fixed plate for unlocking the same.

9. In a reversing switch, the combination of a shaft, means for oscillating said shaft, an insulating block fixed to turn with the shaft, two pairs of contacts located on opposite sides of the block, two line terminals on opposite sides of the block in position to be engaged by the contacts on the block alternately as the block and shaft swing,

means for conducting the currentfrom one contact to the other directly on one side of the block, and crossing conductors'for conducting the current from one contact on the other side of the block to the opposite terminal on the first named side of the block.

10. In a reversing switch, the combination of a shaft, means for oscillating said shaft, an insulating block fixed to turn with the shaft, two sets of contacts located on opposite sides of the block, two line terminals in position to be engaged by the con tacts on the block alternately as the block and shaft swing, means for conducting the current from one contact to the other directly on one side of the block, and means for conducting the current from one contact on the other side of the block to the opposite terminal on the first named side of the block.

11. A reversing switch comprising a shaft, a plate oscillatable on said shaft, means for alternately connecting said plate with the shaft and disconnecting it therefrom, and means for conducting a current through the switch alternately in opposite directions as the plate is oscillated, comprising means for oscillating said shaft, an insulating block fixed to turn with said shaft, two sets of contacts located on opposite sides of the block, two-line terminals in position to be engaged by the contacts on the block alternately as the block and shaft swing, means for conducting the current from one contact to the other directly on one side of the block, and means for conducting the current from one contact on the other side of the block to the opposite terminal on the first named side of the block.

12. In a reversing switch the combination with a casing and shaft therein, of a plate oscillatable on said shaft by external means and having a projection extending from it, two plates mounted to swing freely on the shaft and projecting to a point to be engaged by said projection as the first named plate oscillates, and means operated by said plates for positively turning the shaft in one direction by one plate and in the opposite direction by the other plate, and means for conducting a current through the switch alternately in opposite directions as the first named plate is oscillated, comprising an insulating block fixed to turn with said shaft,

two sets of contacts located on opposite sides of the block, two-line terminals in position to be engaged by the contacts on the block alternately as the block and shaft swing, means for conducting the current from one contact to the other directly on one side of BENJAMIN S. T. BISHOP. HENRY A. JACOB SON. 

